Nickel Asia still intends to ship about 20 million tonnes of nickel ore this year, up 13 percent from 2017, Emmanuel Samson, the senior vice president for finance at the company, said in a phone interview on Tuesday.

Samson's comments followed a Reuters report on Monday that the Philippine government intends to limit the amount of land that miners can develop at any one time to spur environmental rehabilitation, according to a draft government order.

The new curbs come after a crackdown on mining last year that has left more than half the country's mines facing suspension or closure due to environmental breaches.

Shares in Nickel Asia fell as much as 6.7 percent on Tuesday following the Reuters report. Global Ferronickel Holdings Inc , the Philippines' second-biggest nickel ore producer, slumped as much as 7.1 percent.

The mineral deposits at all four of Nickel Asia's mines run deep so the limits in the mining areas should not affect current production volumes, even for its smaller mines, said Samson.

"What we need to do is to perhaps accelerate our rehabilitation of our disturbed areas and we're so used to doing this. Every year we do progressive rehabilitation." he said.

Under the government plan, mines producing up to 1 million tonnes of nickel ore a year will be allowed to work on 50 hectares (124 acres) at any one time. That would increase to up to 100 hectares for mines with output of 9 million tonnes and above. Projects with a processing plant will be allowed up to 162 hectares.

Companies will have to re-forest areas that have been mined above the limits before opening up any new land.

The biggest of Nickel Asia's mines covers nearly 5,000 hectares and the smallest is about 700 hectares.

Nickel Asia, partly owned by Japan's Sumitomo Metal Mining Co, has two nickel processing plants, the only such facilities in the Philippines.

The company sold 17.7 million tonnes of nickel ore last year, mainly to Japan and China, down 8 percent from 2016.

The Philippines was the biggest nickel ore supplier to top market China last year, shipping nearly 30 million tonnes. Indonesia has been the top supplier so far this year after Jakarta relaxed its ore export policy.